AB0644 Incidence of cardiopulmonary complications and survival in early systemic sclerosis (SSc) patients comparing between those with and without elevated serum creatine kinase (CK): inception cohort study
Authors: S. Wangkaew, J. Intum, N. Prasertwittayakij, J. Euathrongchit
Journal: Annals of the Rheumatic Diseases (2022)

Background There has been no prior inception cohort data regarding incidence of cardiopulmonary complications and survival in early SSc patients comparing between those with elevated creatine kinase (baseline CK ≥ 500 U/L) and without elevated CK (baseline CK &lt; 500 U/L). Objectives The aims of this study were to compare: (1) the prevalence of clinical manifestations; (2) incidence rate (IR) of cardiopulmonary complications and (3) survival, between early SSc patients with and without elevated serum CK levels, using inception cohort study. Methods We used an inception cohort of early SSc patients (disease duration from first Non-Raynaud’s phenomenon≤ 3 years) seen at the Rheumatology clinic, Maharaj Nakorn Chiang Mai Hospital, Thailand, between January 1 st 2010 and 31 December 2019. All patients were assessed for clinical manifestations, creatine kinase (CK) levels and underwent electrocardiography (ECG), echocardiography and high-resolution computed tomography (HRCT) at the study entry and every 12 months thereafter. Interstitial lung disease (ILD) was determined by HRCT. Myocardial disease was defined as presence of dilated cardiomyopathy, non-specific cardiomyopathy or suspected primary right ventricular dysfunction assessed by echocardiography. Results One hundred and forty-four patients (84 females, 115 diffuse cutaneous SSc [DcSSc] and 111 anti-topoisomerase I antibody-positive) with mean ± SD age of 53.3 ± 8.9 years, mean disease duration of 11.9 ± 9.2 months and mean follow-up duration of 6.2 ± 2.7 years were recruited. There were 29 early SSc patients with elevated CK (20.1%). Comparing with patients without elevated CK, SSc with elevated CK had significantly higher proportion of clinical manifestations as followings: male gender (58.6% vs. 37.4%, p = 0.038), DcSSc subtype (93.1% vs. 76.5%, p = 0.047) and shorter disease duration (8.2 ± 6.3 vs.12.8 ± 9.5 months, p = 0.009). At enrollment, the elevated CK group had significantly higher prevalence of arthritis (44.8% vs. 25.2%, p = 0.038), weakness (55.2% vs. 10.4%, p &lt; 0.001) and higher modified Rodnan skin score (MRSS) (23.5 ± 10.1 vs. 17.5 ± 10.6, p = 0.005); At last visit, the elevated CK group had significantly higher cumulative prevalence of weakness (58.6% vs. 11.3%, p &lt; 0.001), dysphagia (75.9% vs. 43.5%, p = 0.002), LVEF &lt; 50% (48.3% vs. 12.2%, p &lt; 0.001) and myocardial disease (55.2% vs. 21.7%, p &lt; 0.001). The elevated CK group had significantly higher incidence rate (IR) of: LVEF &lt; 50% (14.24 vs. 2.03 per 100 person-year; incidence rate ratio (IRR) 7.03, p &lt; 0.001), myocardial disease (19.74 vs. 3.87 per 100 person-year; IRR 5.09, p &lt; 0.001) and ILD (60.40 vs. 31.49 per 100 person-year; IRR 1.92, p = 0.006); compared to the non-elevated CK group. The survival rate of early SSc with elevated CK group at 1, 3 and 5 year were 86.2% and 82.5% and 74.3%, respectively. The median survival time of the elevated CK group was lower than those without elevated CK group (6.98 vs. 8.56 years, p = 0.012). Conclusion Our study cohort found that early SSc patients with elevated baseline CK levels are predominant in male gender, DcSSc subtype with shorter disease duration. The elevated CK group has more severe clinical presentations including higher MRSS, arthritis and weakness compared to the non-elevated CK group. In addition, significantly higher incidence rate of: LVEF &lt; 50%, myocardial disease, ILD; and poorer survival are also obviously detected in the elevated CK group. Disclosure of Interests None declared